The structures of the TMTpro and TMT tags are similar in being isobaric and amine reactive, but the TMTpro tag has a longer spacer region and isobutyl proline mass reporter. After MS/MS fragmentation, each TMTpro 18plex tag generates a unique reporter mass (e.g., TMTpro 126-135 Da) in the low-mass region of the high-resolution MS/MS spectrum that is used for relative quantitation of protein expression levels.

The TMT pro134C and TMTpro135N Label Reagents are identical in composition and structure to the other TMTpro 16plex tags, but are not isobaric. Addition of the TMTpro 134C and 135N tags create a 17th and 18th channel for relative quantitation using high resolution Orbitrap MS instruments. These tags are available separately (Cat. No. A52046, A52048), as part of the TMTpro 18plex Label Reagent Set, or as part of the complete 18plex set of reagents in a 96-well plate format.

Features of the TMTpro 18plex Label Reagent Set include:
• Multiplex—concurrent MS analysis of up to 18 samples derived from cells, tissues, or biological fluids
• Robust—increased multiplex capability results in fewer missing quantitative values among samples and higher confidence among replicates
• Efficient—amine-reactive, NHS ester-activated reagents ensure greater than 95% labeling of all peptides regardless of protein sequence or proteolytic enzyme specificity
• Optimized for use—with high resolution Thermo Scientific MS/MS Orbitrap platforms, analysis fully supported by Proteome Discoverer 2.3
• Convenient size—provided in a ready-to-use, single-use format to ensure optimal stability and performance

For high resolution analysis of TMTpro-labeled peptides, the recommended LC column for the Nanospray Flex source is the Acclaim PepMap 100 C18 LC Column (Cat. No. 164942 or 164939). For the EASY-Spray source, the recommended LC column is the EASY-Spray C18 LC Column (Cat. No. ES902 or ES903). When combined with the industry-leading, high resolution Orbitrap instruments and software, TMTpro reagents provide an integrated total solution for quantitative protein expression analysis.